As we can see, there are two arms starting at about $(x,y) = (-14.6,0)$ and $(x,y) = (14.6,0)$. Now I would like to customize ListPLot, so as the arm starting at the left part $(x,y) = (-14.6,0)$, be in green color, while the other one in red. All the other points between the two yellow banana-type areas should be in gray.

Any suggestions?

The complete data file can be found here: data. Obviously, I could not generate simple random data in order to replicate this complicated spiral structure.

Mathematica is a registered trademark of Wolfram Research, Inc. While the mark is used herein with the limited permission of Wolfram Research, Stack Exchange and this site disclaim all affiliation therewith.